Density of Metals Lab

Different materials can be distinguished from one another because they have different properties. One property that is often used to identify unknown materials is density. Density is defined as the ratio of a material’s mass to its volume. By measuring the mass and volume of a sample of material you can obtain an important clue about the identity of the material.

Problem:

Can you identify unknown metals by calculating their density?

Materials:

5 metals samples A – E

Balance

50- ml graduated cylinder

Water

Paper towels

Prelab questions:

1.  What is the formula to calculate density?

2.  What are the units for density of a liquid?

3.  What are the units for density of a solid?

4.  A sample of metal has a mass of 85.6 g and a volume of 12.1 ml. What is the density of metal X?

5.  A metal bar has a density of 19.3 g/ml and a mass of 50.0 g. What is the volume of the bar?

Procedure:

1.  Obtain a kit containing the 5 metal samples and label them according to the directions on the board.

2.  Use the balance to measure the mass of each sample to the nearest 0.01g. Record the masses in the data table.

3.  Fill the graduated cylinder half full of water. Record the volume to the nearest 0.1 ml.

4.  Carefully insert the metal sample without splashing any water. Record the volume of the water plus metal sample.

5.  Repeat for each of the metal samples.

Cleanup and disposal:

1.  Dry the metal samples.

2.  Make sure the balance is left as you found it.

Data and Observations

Data Table
Sample / Mass (g) / Volume of water (ml) / Volume of water + sample (ml) / Volume of sample (ml) / Density (g/ml)

Post Lab

1.  List the metals samples in order of increasing density.

2.  What is the possible identity of each sample? If you are unable to positively identify a metal indicate that by writing “unable to identify.”(check attached chart)

A=

B=

C=

D=

E=

Use the table to answer questions 3 & 4

3.  Find the density of a substance that has a volume of 754cm3 and a mass of 7917g. Using table 1 above identify the substance using the density you found.

4.  A balloon contains helium with a mass of 0.00296014g. What is the volume of helium in the balloon (use table 1 above)?

5.  Write 2 things you learned in this lab.

*****Note that the density of metals actually varies somewhat depending on how the metal is produced. Your measured value may thus be different from the value listed above, but it may still be correct.

Densities of selected metals

Metal / Density (g/cm3)
Aluminum / 2.699
Chromium / 7.13
Copper / 8.89
Gold / 19.33
Iron / 7.86
Lead / 11.347
Magnesium / 1.738
Mercury / 13.596
Nickel / 8.85
Osmium / 22.5
Potassium / 0.87
Silver / 10.6
Tin / 7.184
Zinc / 7.19